The invention relates to a method and to an apparatus for inserting a fastener into a flexible strip or plate that shall constitute a packing structure.
It is known, when packing, to gird the said packing structurexe2x80x94for instance a cardboard structurexe2x80x94with a hoop or the like, illustratively a plastic strip, in order to close or rigidify said packing structure.
This kind rigidification entails the difficulty that the packing structure must be held in place when being hooped and obviously both the packing structure and its hooping means must be handled simultaneously.
Accordingly the inventor conceived of a method and an apparatus for inserting such a fastener into a flexible plate or strip that shall constitute the packing structure and which is fitted with a channel comprising two lips that partly close said channel, said fastener being inserted between these two lips.
The method of the invention is characterized in that it slightly bends the plate or strip transversely to the channel direction in a way to move apart its lips, in inserting the fastener and in substantially flattening again said plate or strip in order that these lips resume their initial positions.
Moreover, in one embodiment of the present invention, the plate or strip is displaced longitudinally relative to its channel during the transverse bending and flattening operations while illustratively the plate or strip shall be guided before being bent by at least one means inserted into its channel.
The fastener also may be advantageously held in position against the bottom of the channel by depressing it during the re-flattening stage.
Preferably the channel lips shall be crushed after the plate or strip has been re-flattened.
Illustratively the fastener being used in the present invention is in the form of a hoop or the like, even though it also may be in other forms such as cables etc.
To carry out such a method, the invention also proposes an apparatus which is characterized in that it comprises a sub-assembly for slightly transversely bending the plate or strip, further an element inserting the fastener and a sub-assembly re-flattening the plate or strip, as well as elements driving the plate or strip in its channel""s longitudinal direction.
In one embodiment mode of the invention, the bending sub-assembly consists of two superposed wheels of which the rims resp. are one substantially concave and one substantially convex surface, the plate or strip being made to pass through said wheels and its channel facing the concave-rim wheel.
In this embodiment, advantageously the element inserting the fastener consists of a guide ramp feeding said fastener, the end of said ramp extending as far as the vicinity of the bending wheels and between them, said fastener moreover being fitted with a circular rib on the concave wheel in order that the rib may press against the fastener during bending.
Preferably the strip re-flattening element comprises straightening fins which pass gradually from an oblique to a substantially plane position, and the apparatus of the invention also comprises a fastener holding-element configured above the straightening fins and optionally in the form of a small bar.
The apparatus of the invention also may comprise an initial holding and guiding element for the plate or strip, which is configured upstream of the bending subassembly as seen in the direction of motion of the plate or strip, and which is a cylinder on which moves said plate or strip, further comprising a roller that rests against the bottom of the channel in said plate or strip. Moreover an aligning guide in the form of a small bar may be configured between the initial holding and guiding element on one hand and the bending sub-assembly on the other.
Advantageously a sub-assembly crushing the channel lips and in the form of compression drums is configured downstream of the re-flattening element.
The elements driving the plate or strip in its longitudinal direction illustratively consist at least in part motors powering at least one of the bending sub-assembly wheels and/or the initial holding and guiding cylinder and/or at least one of the drums crushing the channel lips.
As regards a plate or strip which is additionally fitted with a substantially right-angle flange for the purpose of constituting a bracket, the apparatus of the invention also may be characterized in that the cylinder of the initial holding and guiding element and one of drums of the crushing sub-assembly do comprise a peripheral, circular channel to receive the substantially right-angle flange of the plate or strip.